1. Field of the Invention
This invention is in the field of dishwashing machines and is particularly concerned with a liquid distribution system for delivering wash liquid concurrently to each of two spray arms during the washing operation, the distribution system being automatically disengaged upon termination of wash liquid circulation to provide more convenient access to the dish racks located within the appliance.
2. Description of the Prior Art
Automatic dishwashing machines including a pair of rotating spray arms, one located below the upper dish rack and the other below the lower dish rack are, of course, old. There are numerous examples of this type of machine in United States patents and a few of these are summarized below.
Zurek U.S. Pat. No. 3,009,470 describes a dishwashing apparatus in which there is provided a stationary supply conduit which receives the lower portion of a beveled rotating hub. The hub is mounted on a pivot bearing which extends upwardly from the conduit into cooperative relation with a bearing provided in the hub. The bearing elements are arranged so that under maximum deflection of the hub during its rotation, there is no contact of the edge of the hub with the surface of the conduit. The principal objective of this disclosure was to provide a low friction, substantially clog-proof means for rotatably mounting a reaction type spray device on a conduit supplying the device with liquid under pressure.
Warhus U.S. Pat. No. 3,064,664 provides a dishwashing machine with means for automatic coupling of the fluid supply conduit to the lower spray arm when the lower rack is in operative position. This patent disclosure suggests utilizing an annular expansion coupling fixed about the axial discharge opening provided by the open upper end of the hub portion of the lower spray arm. With an arrangement of this type, the spray arm becomes automatically detached from the liquid supply when the supply means is cut off.
Jenkins U.S. Pat. No. 3,785,566 describes an automatic dishwashing machine in which the pump outlet is provided with a seal member which expands into sealing engagement with the spray arm in response to the delivery of pressurized washing liquid therethrough.